Intersegmental muscles

Description

The small intersegmental muscles — the interspinales muscles, intertransversarii muscles, and suboccipital muscles — in general span a single intervertebral joint. The interspinales and intertransversarii muscles span most of the length of the vertebral column, yet contribute little to any significant vertebral movements. They contain large numbers of sensory neurons within their musculotendinous fasciculi. These spindle-like sensory receptors in the muscles monitor muscle tension. These small muscles, with their poor mechanical advantage, probably function as receptors that monitor the regional movements of the vertebral column and supply feedback that influences the action of the larger surrounding muscles. Associated deep in the junction of the cranium and vertebral column are the four suboccipital muscles. The suboccipital muscles are homologous to the other deep muscles at more inferior vertebral levels, but are developmentally modified and enlarged to function with their specialized vertebral counterparts — the axis, atlas, and occipital bone.